<p>Gob-side entry retaining formed by roof cutting technology is a new mining method. The key to the successful application of this method is to ensure the stability of roadway. Under the action of the roadway roof load, the gangue rib protection structure is in a “prescribed deformation” state. The settlement of the gangue rib protection structure is the same as the sinking of the roof. In order to avoid the failure of gangue rib protection structure under the action of roof load, a targeted sliding protection structure (SPS) was developed. The SPS is a retractable structure with two U-steels connected by clamps. Its mechanical properties are closely related to the number of clamps and the amount of pre-tightening force. In order to grasp the pressure bearing mechanism of SPS, the mechanical model of SPS support is established; the mechanical environment is analyzed. Based on the analysis of the mechanical environment, the laboratory experiment and numerical simulation of SPS under bidirectional load are carried out; the failure mechanism and mechanical properties of SPS are clarified. The results show that under the action of axial load, the SPS avoids buckling failure by sliding. Under the action of bidirectional load, the strength indices of SPS in different pre-tightening force are 100%, 136%, and 174%, respectively. The strength indices of SPS in different numbers of clamps are 136%, 181%, and 231%, respectively. The pre-tightening force and the number of clamps have a significant effect on the axial bearing capacity of SPS. When the number of clamps is two, the pre-tightening force will not change the failure mode of SPS. With the increase of the number of clamps, the failure mode of SPS gradually changes from lateral bending to axial buckling. Based on the above research, a series of support principles of SPS is put forward. The conclusion could provide a theoretical basis for the design and application of some related projects.</p>